The Radiation Linear Accelerator Shared Service (RLASS) is a resource for supporting radiation studies for investigators at the University of Maryland School of Medicine, including the Mariene and Stewart Greenebaum Cancer Center (UMGCC). The shared service currently operates a state-of-the-art research megavoltage linear accelerator (Varian Medical Systems, Palo Alto, CA) that is capable of delivering photon (6-18 MV) and electron (6-18 MeV) radiation beams. This linear accelerator is equipped with state-of-the-art, onboard imaging capabilities that aid in accurate localization of radiation targets. With this combination of technologies, RLASS can replicate sophisticated treatment modalities that are offered as standard of care to patients undergoing radiation therapy. RLASS is a unique resource because most linear accelerators are typically utilized on a full-time basis for clinical radiation therapy treatments. RLASS offers cell culture irradiation, total and hemi-body irradiation, organ- and tissue-specific irradiation in the form of 3D conformal radiation therapy and intensity-modulated radiation therapy, treatment planning and 3D dose calculation capabilities, and onboard imaging. Highly skilled faculty and staff provide investigators at UMGCC with the expertise to design animal protocols and perform dosimetry calculations and measurements to ensure highly reliable estimates of whole-body, partial-body, and organ-specific doses. The effectiveness of this shared service can be gauged from the fact that it has supported the development of advanced radiation delivery and organ-motion management technologies. In addition, it has supported the development of complex nonhuman primate models of radiation-induced injury.